PIR Sensor


Project is based on Holtek’s IC HT7610A, which is a CMOS LSI chip designed for use in automatic PIR lamp, flash or buzzer control. It can operate in 3-wire configuration for relay applications.  In our project we have used relay instead of Traic to connect any kind of load in output, HT7610B IC is suitable for traic and HT7610A for Relay application. The chip is equipped with operational amplifiers, a comparator, timer, a zero crossing detector, control circuit, a voltage regulator, a system oscillator, and an output timing oscillator.

PIR Sensor

Its PIR sensor detects infrared power variations induced by the motion of a human body and transforms it to a voltage variation. If the PIR output voltage variation conforms to the criteria (refer to the functional description), the lamp is turned on with an adjustable duration. The circuit doesn’t required step down transformer and can work directly by applying 110V AC or 220V AC (Capacitor C7 needs to change for 220V AC (0.33uF/275V) and 110V AC (0.68uF/275V)


– Supply Input 110V or 220V AC ( Capacitor Value needs to Change)
– No Step Down transformer required
– IC Operating voltage: 5V~12V
– Load Current 80mA when relay is on.
– Standby current of the IC: 100uA
– On-chip regulator
– Adjustable output duration
– 40 second warm-up
– ON/AUTO/OFF selectable by MODE pin
– Override function
– Auto-reset if the ZC signal disappears over 3 seconds
– On Board Relay to connect output Buzzer or Flash
– On Board LDR to Detect Day/Night operation
– J1 to Set the Mode
– PR1 to set the Sensitivity of the sensor
– PR2 to set the output Turn On Duration
– CDS R11 for Auto Day/Night detection
– (HIGH Voltage On Board) Do Not touch the PCB while power is on


For more detail: PIR Sensor

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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